This invention concerns the technical field of conduits, pipes or tubes, used to transport energy in electrical, optic or fluid form.
1. Technical Field of the Invention
Construction of such transportation networks, often subterranean or subaquatic, therefore requires the juxtaposition and connection of a whole series of elements, such as tubes to make a connection between two joints.
2. Description of the Related Art
Making a connection between two tubes imposes technical constraints associated on one hand with the special application (gas, telecommunications, . . . ) and, on the other hand, with the use of automatic machines for laying those tubes. The use of connection devices that resist strong traction, have compact dimensions and do not need a lot of connection time, so as not to immobilize the machinery too long, is therefore highly sought.
Connection devices are known that make it possible to connect tightly two ends of tubes, having an approximately cylindrical body and two symmetrical, opposing portions to engage the ends of the respective tubes, with each of the portions having hooking means to hold the tube in the connection, and sealing means for such connections; such hooking means on each portion contain:
a truncated chamber arranged in each portion whose large base is located near the center of the device;
a longitudinal rib that projects into the truncated chamber;
and a split ring whose ends are located on either side of the longitudinal rib; said ring is provided with threads inside, and the outer form of said ring is chosen so that at least part of its peripheral surface is supported against the truncated chamber after the end of the tube is engaged to block the tube by any traction on said tube in the opposite direction from its direction of engagement.
However, these devices are not suitable for laying by machine, for example by encouraging blockages when being passed in guides. They also require complex tools to be dismantled on site, for example, to put a new cable in the tube.
Document US-A-2 017 894 also discloses a connection device for metal pipes in which a shrink ring is subject to the action of springs built into said device. The joint action of these springs and the narrow end of the device allows the metal ring to be encrusted in the metal pipes.
Such an embodiment, provided for special application to metal pipes, has an inconvenient design and is structurally complex, making it difficult and expensive to manufacture.
In addition, the stresses of tightening the ring are applied to the end of the connection device, thus embrittling the latter in the area near the narrowed parts.
In addition, tubes made of plastic material are generally wound before they are laid, generating great flexural stresses. These stresses have a tendency to deform and/or round the tubes, which makes them difficult or even impossible to assemble using a connection device.
The subject of this invention is a compact connection device, provided with a fast-hooking system for the tubes to be connected that can be dismantled without any specific tool.
Another goal of this invention is to create a connection device that can be adapted to a potential deformation or ovalization of the circular section of the tubes, and to ensure reliable, tight assembly.
According to the invention, in the type of connection device concerned, the ring is located in the truncated chamber and is deformable elastically, and the inner diameter of the ring is smaller than the outer diameter of the tube in the unstressed or deformed state of said ring, in such a way as to deform elastically and to grip the tube when inserted into said tube.
In another embodiment of the invention, the ring has grooves extending on part of its length starting from one end and distributed radially so as to form a radial tab on the side of the end between each pair of grooves.
In one preferred embodiment, the threading inside each ring has a sharp ridge that can be inserted in the periphery of the tube.
This design makes it easier to put each tube in the connector and improves the tube-ring connection, since it adds notching to the tightening exerted by the ring.
Advantageously, the threads inside the two rings have reverse pitches.
Thus, when the connection is made, the setting in rotation of the body in one direction, simultaneously with the engagement of the tubes in the rings sets the rings in rotation and favors the introduction of the threads of the rings in the wall of the tubes.
This arrangement is also interesting when dismantling the device, since by rotating the body in the opposite direction, it permits simultaneous longitudinal release toward the outside of the body of the two ends of the tube.
In one embodiment, the body has a circular central rib whose diametric faces form stop faces for the face at the end of each tube.
Thus, the engagement of each tube in the body is limited by the stop on the rib, and the contact with the stop informs the operator that he can terminate the connection by pulling the tubes toward the outside to cause additional tightening of the tubes by retracting the rings cooperating with the wall of the corresponding truncated chamber.
The invention also concerns a subterranean or subaquatic installation conduit having at least two installation tubes and at least one connection tube.
The advantage of the connection device in the invention is mainly its great structural simplicity and the reduced number of parts of which it is composed.
This increases the reliability of the device and reduces its cost.